Influence of Alkali Metal Cations in the Formation of the Heterobimetallic Actinide tert-Butoxides [AnM3(OtBu)7] and [AnM2(OtBu)6] (AnIV = Th, U; MI = Li, Na, K, Rb, Cs)

These are the raw data the compound ThCs2, refined as a merohedral twin. The following is the abstract of the corresponding paper.

Heterobimetallic tert-butoxides of alkali metal cations and tetravalent actinide centers exhibit two distinctive structural motifs, [AnM₂(O^tBu)₆] and [AnM₃(O^tBu)₇] (An^IV = Th, U and M^I = Li, Na, K, Rb, Cs), evidently govern by the size of the alkali metal ions. Both [AnM₃(O^tBu)₇] AnM3 (An^IV = U, M^I = Li; An^IV = Th, M^I = Li, Na) and [AnM₂(O^tBu)₆] AnM2 (An^IV = U, M^I = Na – Cs; An^IV = Th, M^I = K - Cs) compounds are obtained in nearly quantitative yields by reacting the actinide and alkali metal silyl amides with excess of tert-butyl alcohol. The AnM3 complexes form a cubane-type coordination motif, whereas the AnM2 complexes display a geometry resembling two face-shared bipyramids. The sodium derivatives of thorium and uranium (ThNa3 and UNa2) allow to determine the structural transition threshold as function of the ratio of the ionic radii, r_i(An^IV)/r_i(M^I). The AnM3 complexes are formed for ratios above 0.92 and the AnM2 type is formed for ratios below 0.87. All compounds are unambiguously characterized in both solution and the solid-state via NMR and IR spectroscopic studies and single crystal X-ray diffraction analyses, respectively.